I know "a person" that had to back up about 1/4 of a mile when he got off the interstate and looked for an advertised fuel stop that he couldn't see from the exit ramp. The road was a dead end with no turn around! It was at night, no other vehicles came by, and there was only one curve. That took a long time, it was very hard to see. "He" had to G.O.A.L. many times. "He" said "he" was sweating bullets in Janurary, but it turned out OK. He also remembers telling dispatch about a long traffic hold up in a construction area. Now, if he doesn't see the fuel stop from the exit ramp, he just gets right back onto the interstate.
Thankfully I've never had a side of the road bathroom emergency beyond taking a leak. The closest I ever came to the next level was having to puke into my coffee cup while driving. That would have been messy if not for that bit of quick thinking.
We didn't use this when we were OTR, but we use it when we go camping. Get a 5 gallon bucket. Buy "Doodie Bags" (Don't laugh, that is what they are called! LOL) These are bags that you open and put over the top of the bucket. They make plastic toilet seats that snap on the top of the bucket (seat and lid). When done, fold the inner liner into the exterior bag and it double zips to close. Like I said, we use these when camping and it would have come in handy a time or two while we were on the road! If you are sick with a bad cold, flu or food poisoning, let your dispatcher know and chances are, they will send another truck to you with an empty trailer and they will take your loaded trailer and deliver it to the customer. Wrong street? As others have said, see if you can safely turn around. If not, you may have to back out a ways until you can find a spot large enough to turn around. Or, you may have to call the police. They may not be happy with you for taking a wrong turn, but they would rather assist you in getting out instead of having to show up after you have take out some power lines and then having to do a report on it.